Production of paraffins



Dec. 8, 1953 M. P. MA'ruszAK PRODUCTION oF PARAFFINs Filed Dec. 18, 19452 Sheets-Sheet l Dec. 8, 1953 A M. P. MATuszAK 2,662,103

PRoDUcTIoN 0F PARAFFINS Filed Dec. 18, 1945 2 sheets-sheet 2 v flsoBUTANE coNDENsER LAYER Di lLI F' 4| cooLER Lx y v 43 -"j\ HF LAYER T"4o INVENToR.

FIG 2 ME MATuszAK BY MMM (WMU ATTORNEYS Patented Dec. 8, 1953 APaoDUc'rroN or PARAFFINS Maryan PMatuszak, Bartlesville, Okla., assignerto Phillips Petroleum Company, a corporation of DelawareApplicationpecember 1s, 1945, serial No. 635,764`

This invention relates to the production of paraflins from isopentaneand more particularly to the production. of isobutane and parainsheavier than isopentane from isopentane.` .Still more particularly, itrelates to production of iso-v butane and paraflins heavier thanisopentane from isopentane by a process involving .simultaneousdisproportionation and alkylation of isopentane with a low-boilingaliphatic olefin having at least 3 carbon atoms per molecule and with acatalyst consisting of liquid substantially anhydrous hydrofluoric acideither alone or promoted with up to per cent of boron uoride based onthe total Weight of catalyst.

This application is a continuation in part of my co-pending application,Serial No. 467,872, filed December 4, 1942, now Patent 2,399,368 issuedApril 30, 1946.

The principal object of this invention is to increase the total yield ofhigher-boiling and normally liquid or gasoline-range parains producedfrom a given weight of an oleflnic reactant in hydrouoric acid-catalyzedconversion of isopentane to heavier parafns.

Another object is to produce high yields of isobutane and isohexanesfrom isopentane and an olefin in the presence of liquid substantiallyanhydrous hydrofluoric acid allrylation catalyst.

Another object is ,to provide a process of the foregoing type whereinisoparains heavier than visopentane and having high octane rating areproduced in greater overall yield fromA given quantities of isopentaneand aliphatic olefin.

Numerous other objects of the present invenv tion Will be apparent tothose skilled in the art from a consideration of this specication takenin conjunction With the accompanying drawing wherein Fig. 1 portraysdiagrammatically one arrangement of equipment which may very advantagevously be employed in carrying out the present invention, and Y Fig/2portrays a modification' ofthe reaction .l vessel wherein the reactionis' carried out in a combined reaction-fractional distillation column. Ihave now found that by the employment of suitable proportions ofreactants and of suitable reaction conditions which are fully detailedhere- 4 claims. (Cl. 26o-683.4)

under certain yconditions a surprisingly large proportion of theisopentane is converted to isobutane and isohexanes concurrently Withprimary alkylation of a minor proportion of the isopentane, so thatyields of hexanes and higherboiling gasoline hydrocarbons of at least400 and even as high as 500 or more per cent by Weight of theolefln'charged are obtained.

The isobutane produced by the disproportionation may be used as feedstock for other processes, as fora process in which it itself isalkylated. I

' have found that in the interest of an increased yield ofhigher-boiling or gasoline hydrocarbons (C6 and heavier) from thedisproportionationalkylation, it is preferable to remove the isobutanefrom the reaction mixture as soon as possible after its formation, 'andthat it is preferable not to recycle the isobutane to this particularprocess. On the contrary, better yields of higher octane hydrocarbonsare obtained if the isobutane is'alkylated With an olefin in a separatezone.

ASubstantially immediate removal of the isobutane as soon as it isformed may be accomplished in any suitable manner. For example chargingand Withdrawal rates and residence time in a continuous process may beso adjusted that the reaction mixture is promptly Withdrawn from thereaction zone and passed to suitable steps for the rapid removal ofisobutane. It is desirable to avoid alkylation of isobutane in thedisproportionation-reaction Zone. Removal of isobutane from the reactionZone is additionally desirable because it facilitates the desiredreaction, namely, disproportionation In many cases it will be founddesirable to effect substantially immediate removal of isobutane fromthe seat or center of reaction by conducting the reaction in afractional..distillation column.

The molar ratio of isopentane to olen charged to the reaction zoneshould be at least 5:-1 and preferably is` at least 7:1.` It may rangeas high as 10:1 or even higher, up to 20:1. This ratio has reference tothe external feed, i. e., to the total isopentane and olefin introducedto the reaction zone. This is to be distinguished from the internalmolar ratio, i. e., the molar ratio of isoparaiiin to olefin in thereaction zone itself. As

Will be obvious to those skilled in the art, because of very rapidconsumption of olen, the internal molar ratio of isoparaflin toolefinmay be exceedingly high, for example as high as :1 or even 1000: l. Inthe case of continuous operation, the 'external molar ratio .ofisopentane to olen may be determined from the relative amounts ofisopentane and clen charged at any instant. In batch type operation,where the oleiin is usually added over an extended period of time t thereaction zone containing the isopentane and the hydrouoric acidcatalyst, the molar ratio reerred to above is that of the totalisopentane charged to the total olein charge.

The amount of 'hydrofluoric acid employed Yas catalyst may vary withinWide limits. Ordinarily it will be such that the volume of hydrofluoricacid is at least equal to that of the hydrocarbons present in thereaction zone. Usually thehydrofluoric acid will be present in suchamount that it will form a separate acid phase, thereby requiringprovision of suitable means for agitat ing and securing intimate contactbetween the hydrocarbon phase and the catalyst phase. :The volume ratioof hydrofluoric acid to hydrocarbons may range from 1:10 up to 2:1.

. The reaction temperature may range from 40 to 3Go" F. Temperaturesbelow 40 F. are disadvantageous and are lseldom employed. The preferredtemperature range is from lilOto Y20.0 F. Employment of temperaturesWithin this range gives considerably higher'yields-andis preferred.

The pressure in the reaction zone .should be sufficient to maintain thehydrocarbons and the hydrofluoric acid in liquid'ph'ase.

Ordinarily I employ a catalyst consisting of substantially anhydroushydrofluoric acid. This catalyst should preferably not contain 7morethan a few per cent o'f Water., vsay not over A5 per cent. If thehydrocarbons available contain entrained or dissolved Water to anysubstantial extent, appropriate measures should be .taken to kremovesuch water prior rto charging the hydrocarbons to the reaction yzone,.so that the hydrocarbons ,charged are essentially anhydrous. Thisprevents the accumulation of water .in the hydroluoric acid which has ,avery great alnity .for Water. Accumulation of Water in the catalystfisundesirable because tit destroys its activity rand :requires that .anobjectionably ,large proportion 'of the catalyst be continuouslyrejected from vthe system since .hydrofluoric acid andwaterlformanazeotrope which cannot be -resolved economically 1in vany way'novv knownto the art.

In some cases, it maybe desirable toemploy a vcatalyst consisting ofsubstantially anhydrous hydrofluoric acid promoted witha knnlnorproportion of boron uoride. For example, the 'amount of boron fluorideemployed may irange from va trace up to but not exceeding 10 Weight percent of the total catalyst. tion of hydrouoric acid and causes thereaction to proceed .somewhat more expeditiously. However, the expenseconnected with theuse of boron iiuoride and Vrecovery thereof .may make.its :employment unwarranted.

As the olefin I may use any Ylow-boiling aliphatic olen having at least3 caxbonatoms 'per molecule. Thus .l may use rany of the C3 to :Csoleiins including propylene, any of .the butylenes and any of theamylenes. Mixtures of any'two or more of the C3 Vto VCs oleiins maybeused.

The 'reaction time .may vary within quite Wide limits depending upon theconditions underwhich the reaction is carried out. Normally .the reac-.tion time will not be less than 5 minutes nor greater than 1 hour. Thehydrocarbons `should be held in the reaction zone long enough to:accomplish substantially complete consumption Yof the oleiin andformation'of the desired .products to the desired extent. It is believedthat theol'en Boron fiuoride promotes the acis consumed substantiallyentirely by allrylation of a minor proportion of the isopentane. Thereaction is characterized by the formation of isobutane from isopentanein an amount ecual to at least 150 and occasionally as high as 250Weight per cent of the olefin charged. It is further characterized bythe formation of Ce and higher parainsfrom isopentane tothe extent of atleast 400 vand occasionally as high as 5Go or more weight per cent ofthe olen. The yield of Apentane-free liquid hydrocarbons produced bytheprocess 'of the present invention is at least 130 weight per cent andoften as high as 200 or even ..230 `Weight per cent of the theoreticalalkylationyield. In most cases at least 30 volume per centofthe Ca andhigher paranins produced by Ithe process arer hexanes (isohexanes) whichare very valuable. In addition my process yields substantial percentagesof each of higher branched chain paraiiins, namely, heptanes, octanes,nonanes and .decanos and heavier.

The major reaction occurring in the process Aof Vthepresent.inventionisdisproportionation of the isopentane to isobutane and lto heavier thanisopentane.

Aisoparaffins A 'minor reaction `is lthe alkylation of a portion of theisopentane With the olefin employed. The olefin acts to alkylate aminorproportion only of the isopentane. The disproportionation of theisopentane takes place .very expeditiously intheprcsence cf thereactants rnotesth'e disprcportionation of the remainder of theisopen'tane .'to' a 'very pronounced degree.

The process of my inventionmay `very advantageously be `carried out in acombination reaction-fractional distillati-on column to which the'isopentane and `the olefin in the `proper external imolarratiofmay becharged continuously. Liquid substantially anhydrous hydrofluoric acidmay be injected continuously at a point or several 'points of thecolumn. This hydrouoric acid may serve as the reux for the column. Thebottom 4of the vcolumn is reboiled in the usual way. The yolefin may beintroduced with the isopentane or .at another point in the column. Itmay be introduced at Aa multiplicity of points along the column. Sincethe olefin is substantially immediately consumed by reaction none goesout in the overhead vapors. The overhead from the column 'is anazeotrope of isobutane and hydrogen uoride. This mode of operation isespecially advantageous because the isobutane formed by'disproportionation is immediately removed from the zone of reaction byfractional distillation. The overhead vapors of isobutane andhydrof1uorio-acid may be condensed and the resulting liquid condensate.subjected to layer formation. The isobutane layer is withdrawn from thesystem and may be 'passed to a separate alkylation step wherein 'it isalkylated with an olen. The acid layer is recycled to one or more pointsof the column as a source of hydroiiuoric acid for the reaction and as aredux for the column. The column `may be operated under any suitable lowsuper-atmospheric pressure which is sufficient tn hold the temperaturesin the column at the de- Isired level. The zone of the bulk of thereaction should be between 40 and 300 F. and preferably between and 200F. The top temperature 'of vthe column will be the boiling point of theisobutanehydrouoric `acid azeotrope under the column pressure; Thebottom temperature should be at least suiciently high to insuresubstantially complete removal of isopentane from the withdrawn kettleproduct so that the isopentane charged to the column is not allowed toescape therefrom but is held therein until it is converted to higher andlower isoparafns.

Where the reaction is conducted in a fractional distillation column inthe manner just described, the amount of hydrcfluoric acid present mustbe suicient to form a separate liquid acid phase in the major reactionzone in the column. Although at times it may be desirable to providespecial means for attaining intimate contact between the acid phase andthe hydrocarbon phase wherever they are present in the column,ordinarily the bubble trays or column packing will provide the necessaryintimacy of contact. However, if desired, additional provision may bemade for obtaining such Contact. The selection of suitable means foraccomplishing this result will be obvious to those skilled in the art.

The bottoms product from the reactor-,fractionator is treated in anysuitable manner to recover the valuable products contained therein,namely, the parains boiling above isopentane. If an acid phase ispresent, this bottoms product is passed to the usual settler where thehydrocarbon is drawn oil separately from the acid phase, which isrecycled to the column.

In Fig. l of the drawings, isopentane charge'L via line I to reactor 2.Olein enters the system via line 3; hydrcuoric acid enters by line if itis desired to use a small amount oi boron fluoride as a promoter, it maybe fed in via line 5, The olen maybe admixed with the hydroiluoric acidprior toV entry into 2; but preferably it may be fed in separately asvvia line l or it may be fed in admi'xture with the iscpentane as Vialine Reactor 2 is provided with the usual means for maintaining thedesired ternperature therein and for obtaining the desired degree ofcontact between the acid phase and the hydrocarbon phase. The reactionkeiiluent is passed via line 5I to settler 8 from which the hydrocarbonlayer is fed via line 52 to deisobutaniaing column 3. rEhe acid layer iswithdrawn via line 53 and recycled via line 5d to reactor 2. Ordinarilya suitable portion or" the acid layer is continuously rerun as in unitIii prior to recycling. The portion to be rerun is passed via line 55 torerun unit Il) (which is of known type) and the rerun HF is returned Vialine 56 to line i and reactor 2.

The overhead fraction from deisobutanicing column may be passed directlyvia lines 5l, 5S and 52 to a separate alkylation unit I i wherein it isalkylated with an olefin using hydrofluoricacid as the catalyst.Ordinarily this overhead fraction will contain substantial proportionsof hydroi'luoric acid. Removal of such hydrofiuoric acid is notnecessary prior toalkylation in unit I i. If desired, however, theoverhead from column 9 may be fed to unit I2 and/or unit i3 for rem-ovalof hydroiiuoric acid and light gases such aspropane and lighter,respectively. Hydroiiuorie acid separated in unit i2 may be recycled vialine It. The thus puried isobutane be fed toralkylation unit II. tageousto do so, there may be occasions when it will be desired to recycle theisobutane derived from the overhead. of column 9 to the reactor 2. rhismay ber done by means or" lines I5 or it.

The isobutane overhead traction from column- While it is distinctlydisadvan-v Y 6 wherein hydrofuoric acid may be removed in known manner.The thus puried isobutane may be-fed to alkylation unit I I by means oilines 6d, 6I and 62. The separated HF is discharged from unit I2 vialine 64 whence it be discharged from the system via line 65 and/orrecycled to reactor 2 Via line ld. Alternatively the isobutane leavingunit I2 via line Gti may be fed via line t3 `into separation unit I3wherein light gases namely propane and lighter are separated in knownmanner. The light gases are discharged from unit I3 and the system vialine 5E. The so puried isobutane leaves unit I3 via line d'1 and is fedVthereby and by line 62 to alkylation unit i l.

If desired the isobutane overhead fraction from ycolumn 9 may be passedvia lines 53, 6I to unit I3 for the separation of light gases only, theresulting isobutane free from such gases as propane and lighter thencebeing passed via lines 6'! and'62 as before.

Extraneous HF is fed to alkylation unit I I ria line 68 and olefin isfed thereto via line The bottoms product from column 9 is fed via line10 to deisopentanizing column I? which removes overhead the unreactedisopentane. This isopentane is withdrawn via line 'Ei and may berecycled to unit 2 via line I t. -If desired a portion of the overheadfrom column l? may be discharged from the system via line i2. Thebottoms product from column il consists of paranns heavier thanisopentane and contains not only the alkylateformed in unit 2 but alsothe Ce and heavier paraiiins formed by disproportionation of isopentanetherein. This product may be treated in any suitable manner to recoverits componente, for example, it may be passed via lines 73, 'M and I5 tofractionation system it for separation into several high octanefractions as ind"- 'cated YIi desired, a portion or all of the C@ andheavier bottoms fraction withdrawn trom column I1 via line 'E3 may bewithdrawn from the system via line In many cases it may desirable topass the bottoms product from line 'F3 -through lines 'I4 and 'il to acolumn E@ wherein the isohexanes are separated overhead via line "i8from. the heavier material which is withdrawn as bottoms product vialine '19. This bottoms product may conveniently be fed from line 'i9through line 'I5 to the fractionation system. it for further resolutioninto the desired fractions thereof.;

If desired, the isohexanes fraction separated as overhead in column 2limay be fed via line 'it to an alkylation unit 2l wherein it is alkylatedwith olefin introduced via line 8-5 using introduced via line 8l' as thecatalyst.

The alkylate-containing hydrocarbon miXtiu-e formed in units II and ZImay if desired be fed via lines 22 and 23 respectively to the commonfractionation system I9.

Fractionation system i3 is of a type well known to the art and mayconveniently comprise a series of fractional distillation columns. Ifthe isohexanes were. not previously removed by the use of column 2Q theyare separated in system i9 as a fraction withdrawn via line 82.. Theisoheptanes may similarly be withdrawn as a separate fraction via lineS3. The octanes and heavier may be withdrawn via line 84.

In Fig. 2 of the drawings, there is portrayed equipment for carrying outthe reaction o the present .invention in a fractional distillationcolumn 30. Column 3S is equipped with the usual bubble trays asindicated by the dotted linesand with the usual reboiler 3 I. Theisopentane either L cy itself or in adinixture with the olen isintroduced at an intermediate point in the column, usually around themidpoint, by means .of lin-e 32. Optionally the olen may be separatelyintroduced at one or a plurality7 of points which may be below the pointof isopentane entry as Yshown in the drawing, or which might in certain`cases be above the point of isopentane entry. For this purpose line 33and associated injection lines may be provided. The hydrofluoric acid inliquid form .s

is introduced via line 34. The overhead vapors consisting essentially ofisobutane and hydrofluoric acid are removed Via line 35, cooled incondenser 33 to liqueiy there, and the resulting liquid condensatesubjected to layer separation in settler 37. The isobutane layer isWithdrawn from settler 3? by line The Aacid layer `is drawn oi by line3S and is recycled via line 39A for admixture with incoming freshhydrouoric acid in line 3s. The reboiled bottoms product, consistingessentially of parafns boiling valcove isopentane, is fed via line le tosettler lll when aseparate acid phase is present. The hydrocarbon layeris Withdrawn via line i2 and fed to a recovery system which may besimilar to that shown in Fig. l or any .other fractionation system. Theacid layer is withdrawn by line 43 and recycled via lines 39 and 33A toline 34 and to column 3'3. If the bottoms product in line 40 vdoes notcontain a separate phase of hydrofluoric acid, it may be passed directlyvia line it to the recovery system. It is often desirable to cool theIbottoms product flowing in line @il in order to get a better separationin settler IH. For this purpose cooler may be provided.

While it is generally preferred to re-introduce the hydroiiuoric acidflowing in line 39 to the top of column Si? by means of lines 33A and34, I may, as is indicated by Fig. 2 of the drawings, introduce aportion ci this recycle at other points in column 9. For this purposeline 55 Aand associated inlet lines Lli, t3, l-El, 5e and 59A may beemployed.

The following examples are illustrative of some of the many aspects ofthe invention but are not necessarily limitative.

Examples l' to VI Data for several batch-type runs Afor the conversionof isopentane in the presence of hydrofluoric acid, using variousolenns, are presented together, for the sake of brevity and conciseness,in the following tabulation.

In the run with propylene, Example I, the amount of isobutane formed wasnot determined, but it was probably approximately molecularly equivalentto the yhexanes (isohexanes), which constituted over S per cent of theliquid product. This run was made at an insuiciently high temperaturefor optimum results, but it is clear that a high extent ofdisproportionation occurred in spite of this fact.

Among other things, it may be noted from these data that the yield ofdepentanized liquid product was much higher than that to be expectedfrom ordinary alkylation, being as high as over twice the theoreticalalkylation yield computed on the basis of one molecule of olein reactingwith one molecule of isopentane. Yields even higher than those shown areobtained at relatively higher temperatures, such as temperatures in thepreferred range of 100 to 200 F. With respect to the two runs made withisobutylene, the yield was highest in the run that was made at therelatively higher temperature. In all these runs', more .than one.molecule of isopentane reacted per molecule -of olefin to 'givehigher-boiling parafiins; indeed, in the higher-*temperature run withisobutylene over :five molecules of isopentane reacted per molecule ofolefin. Since oleiins, because of their relatively greater readiness toreact chemically, are in general more valuable than the correspondingparains, a major advantage of the disproportionation- -alkylation hereexemplified is obvious.

Disproportio-nation-alkylation of isopentane Example I II i III 'IV V VIOlefm 03H6 -CiHa i-C4H3 1-C4Hs 2-C4Hrs 05H10 Temperatllr0,` F- (i5-79 i-(i4-86: 38-61 66400 I 68-102 -73`100 Reaction time, min 35-70 l0-30 l10-30 i l0-30 10-30 l 9-31 Isopentane/olefin A (mol.) .(feed) v. 7, 258. 75 7. 62 8. 31 '7..5 E 10. 2 Hydrocarbons/HF ol, 7.6 l1 1 'l l'Iso'bu'tane Iormcd, f

Weightperceut ci olen 261 200 '155 187'` 165 Peutaue-frec liquid 2product:

Yield- Weight percent of olen 406 535 443 '405 l 445 437 Weight pericent of theoretii cal Aallrylation yield 136 234 194 177 195 216Composition, vol. percent:

Eemnes." 30. 7 45. 2 42. 3 37. 7 41.4 49. 5 Heptaues 8. 8 10.2 9. 0 5.16, 7 7.5 Octanes 41.7 5.8 11.6 6.4 7.7- 3.4 Igonanes l 2%7). 3 g 37. 032. 2 21. 9 ..ccaues .5f 15.4 Heavier 3.4 2. o 4. 3 138 12- 0 2. 3

Total 100.0 100. 0i '100.01 100.0 100. 0 100.0

Aviation-'gasoline I fraction: f

Cut point, F.. 338 .289` 289 284' 293. 295 Yield,

ceut 81.4 76. 2 80. 7 S4. 3 78.0 Reid vap pressure, lb 3. 2 4. 65 4.604. 45 4. l0 5.15 Gravity, APL 71. 2 75. 6 '75. 2 74. 6 73. 7 76. 4 ASTMdistillation, F.-

First drop.. 138 143 143 142 145 140 10% evap 173 153 155 155 161 15050% evap 213 175 177 183 191 166 evap 274 264 273 271 268 284 Endpoint.. 344 334 328 321 336 332 ASTM octane 0 cc. TEL. 75. 0 75. 0 76. 274. 6 79. 2 72. 2 l cc. TEL-. 86. 3 88.7 90.1 87. 7A 89. 3 86. 3 Totalproducts, weight percent of olefin .f 796 643 500 632 602 In the abovetabulation two figures are given for temperature. lThe first figure isthe ternperature at the start of the reaction, and the second figure isthe temperature at the end of the reaction which is exothermic.Likewise, two numbers are given for reaction time. These iigures givethe shortest and the longest times that the olen was inthe reactionzone. These were batch-type runs in which the olefin was addedlgradually over an extended period of time.

asesinosw 9 tion unit such as unit H in Fig. 1, preferably in thepresence of hydrofluoric acid as catalyst.

This procedure is much more 'advantageous than Y recycling the isobutanetogether with unreacted isopentane back to the first unit 2, for theoverall yield of gasoline-range liquid parafns for the two-stageoperation is considerably larger than for the one-stage operation.`Furthermore, the liquid Yproduct from the alkylation of isobutane isconsiderably higher in octane rating than the liquid product from thedisproportionationalkylation of iscpentane with ther same oleiin; forexample, the aviation-gasoline'.allrylate from hy-V droiluoric acidalkylation of isobutane with isobutylene has an octane number of about95--96, which is 20 units higherthanigtheyalues; given; in the foregoingtabulation for the aviation-range fraction of the product from theyconversionof isopentane. Hence, because of the present de-k mand forhigh-octane aviation gasoline, the two@l stage operation yielding twogasolineLrange prod`Y ucts is relatively more advantageous than theonestage operation having combined recycling of isobutane and unreactedisopentane. However, this .one-stage opera-tion is not outside thebroadest scope of this invention.

The isohexanes produced by the disproportionation may be similarlyadvantageously separated from the product, as by fractional distillationand may be used as such for blending in motor fuels or may be alkylatedwith an olefin as in unit 2l of Fig. 1, preferably in the presence ofhydror'luoric acid to give paraiins of different volatility.

It should be observed that the reactions promoted in accordance withthis invention do not comprise secondary reactions such as for ex amplethat of cracking subsequent to ordinary alkylation. In suchcracking-alkylation, the reactant isoparain is alkylated with an oleiinas in ordinary alkylation and the resulting alkylate is allowed to crackinto smaller compounds. Obviously, such cracking-alkylation results inlittle or no improvement in the over-all yield of parafrlns heavier thanthe original parain, whereas by the present invention the over-all yieldof such heavier parafns is markedly increased, and to a surprisingly andquite unexpectedly high degree in the light of past knowledge. Briefly,instead of promoting reactions following alkylation, the present processpromotes reactions preceding or accompanying alkylation.

In accordance with this invention, certain desirable reactions areselectively promoted that ordinarily occur to only relatively minorextents in alkylations of parans with olefins in the presence of liquidacid-type alkylation catalyst. Because the invention may be practisedotherwise than as speciiically described or illustrated, and becausemany modifications and variations within the spirit and scope of it willbe obvious to those skilled in the art of hydrocarbon conversion, theinvention should not be unduly restricted by the foregoing specificationand examples.

I claim:

l. An improved process for converting isopentane to higher-boilingisoparaflins boiling in the gasoline range, which comprises chargingisopentane and a low-boiling aliphatic olefin having at least threecarbon atoms per molecule, in a molar ratio of isopentane charged toolefin charged of at least 7:1, to an intermediate portion of combinedreaction-fractional distillation zone, introducing a liquid hydrouoricacid alkylation catalyst to the upper portion of said zone as yal liquidreflux for said distillation, maintaining in an intermediate reactionportion of said theextentv of at least Weight per cent of the itheoretical alkylation yield, at least 30 volume per cent of said Cs andhigher paramns being isohexane; removing as an overhead distillateiromsaid zone a mixture comprisingr hydrogen iiuorideand isobutane andlighter hydrocarbons, cooling and condensing said mixture and separat-.ing a liquid hydrocarbon material from liquid hydroiluoricacidjreturning at least a portionof said liquid hydrofiuoric acid tosaid zone as said reflux, separately alkylating isobutane'contained insaid liquid hydrocarbon material to produce normally liquid isoparaiiinsboiling in the gason line range, passing a resulting crude alkylate to aseparating means, removing from the aforesaid reaction-fractionaldistillation Zone as a'highM boiling product a liquid hydrocarbonmaterial free from hydrogen fluoride and comprising C6- andehigherhydrocarbons produced in said zone, passing the last said liquidhydrocarbon material to the aforesaid separating means, and removingfrom said separating means as a product of the process an isoparafiinichydrocarbon material comprising isoparafns boiling in the gasoline rangeproduced from isopcntane in said zone, and produced from said isobutanealkylation.

2. An improved process for converting isopentane to higher-boilingisoparaiiins boiling in the gasoline range, which comprises chargingisopentane and a low-boiling aliphatic olefin having at least threecarbon atoms per molecule, in a molar ratio of isopentane charged toolefin charged of at least 7 :1, to an intermediate portion of combinedreaction-fractional distillation zone, introducing a liquid hydroiiuoricacid alkylation catalyst to the upper portion of said zone as a liquidreflux for said distillation, maintaining in an intermediate reactionportion of said zone a reaction temperature, a ratio of liquidhydroiluoric acid catalyst to liquid hydrocarbons from 1:10 to 2:1, anda reaction time between 5 and 6D min utes and sufficient to effectcomplete reaction of charged olefin and formation of isobutane to theextent of at least 151) weight per cent of said olefin and of Cs andhigher isoparaflins to the extent of at least 400 weight per cent ofsaid olefin and to the extent of at least 130 weight per cent of thetheoretical alkylaticn yield, at least 3c volume per cent of said Ce andhigher paraiiins being isohexane, removing as an overhead distillatefrom said zone a mixture comprising hydrogen fluoride and isobutane andlighter hydrocarbons, cooling and condensing said mixture and separating a liquid hydrocarbon material from liquid hydrouoric acid,returning at least a portion of said liquid hydrofluoric acid to saidzone as said reflux, removing from the aforesaid reactionfractionaldistillation Zone as a high-boiling product a liquid hydrocarbonmaterial free from hydrogen fluoride and comprising Cs-and-higherhydrocarbons produced in said zone, passing the last said liquidhydrocarbon material to separating means, and removing from saidseparating ll means as a product of the processy anv isopara'f.-v nichydrocarbon material comprising iso-parait?V ns boiling in the gasolinerange produced from isopentane in said zone.

3. Anv alkylation process which comprises reacting isobutane with anolen under alkylating conditions, separately alkylating isopentane withpropylene in the presence of hydrogen fluoride at a temperature of fromabout 75 F. to about 150 F. While maintaining a molar ratio ofisopentane to propylene of about 7.2511, whereby to produce asubstantial amount of isobutane concurrently with the alkylatedisopentane, and supplying the isobutane thus produced to therst-mentioned alkylating step.

4. An alkylation process which comprises reacting isobutane with anolefinl under alkylating SRIES conditions, separately batchwisealkylating isoof isopentane to propylene of about '7.25 :21, Whereby toproduce a substantial amount of i'sobutane concurrently with thealkylated isopent'ane, and supplying the isobutane thus produced t'o thefirst-mentioned alk-ylating step.

MARYAN P. MATUSZAK.

References cited in the nie of this .patent UNITED STATES PATENTSNumber` Name Datei 2,227,559 `Stevens et al Jan. 7, 1941v 2,255,610Bradley Sept. 9, 19'4-1 2,267,730 Grosse et al. i Dec. 30, 19412,311,531 Fulton Feb. 16, 1943 2,322,800 Frey 1 June 29, 1943 2,365,426Molique Dec. 19, 1944 2,399,368 Matuszak Apr. 30, 1946 2,405,993 BurkAug. 20, 1946 2,436,483 Newman .7 7 Feb. 24, 1948

1. AN IMPROVED PROCESS FOR CONVERTING ISOPENTANE TO HIGHER-BOILINGISOPARAFFINS BOILING IN THE GASOLINE RANGE, WHICH COMPRISES CHARGINGISOPENTANE AND A LOW-BOILING ALIPHATIC OLEFIN HAVING AT LEAST THREECARBON ATOMS PER MOLECULE, IN A MOLAR RATIO OF ISOPENTANE CHANGED TOOLEFIN CHARGED OF AT LEAST 7:1, TO AN INTERMEDIATE PORTION OF COMBINEDREACTION-FRACTIONAL DISTILLATION ZONE, INTRODUCING A LIQUID HYDROFLUORICACID ALKYLATION CATALYST TO THE UPPER PORTION OF SAID ZONE AS A LIQUIDREFLUX FOR SAID DISTILLATION, MAINTAINING IN AN INTERMEDIATE REACTIONPORTION OF SAID ZONE A REACTION TEMPERATURE BETWEEN 100 AND 200* F., ARATIO OF LIQUID HYDROFLUORIC ACID CATALYST TO LIQUID HYDROCARBONS FROM1:10 TO 2:1, AND A REACTION TIME BETWEEN 5 AND 60 MINUTES AND SUFFICIENTTO EFFECT COMPLETE REACTION OF CHARGED OLEFIN AND FORMATION OF ISOBUTANETO THE EXTENT OF AT LEAST 150 WEIGHT PER CENT OF SAID OLEFIN AND OF C6AND HIGHER ISOPARAFFINS TO THE EXTENT OF AT LEAST 400 WEIGHT PER CENT OFSAID OLEFIN AND TO THE EXTENT OF AT LEAST 130 WEIGHT PER CENT OF THETHEORETICAL ALKYLATION YIELD, AT LEAST 30 VOLUME PER CENT OF SAID C6 ANDHIGHER PARAFFINS BEING ISOHEXANE, REMOVING AS AN OVERHEAD DISTILLATEFROM SAID ZONE A MIXTURE COMPRISING HYDROGEN FLUORIDE AND ISOBUTANE ANDLIGHTER HYDROCARBONS, COOLING AND CONDENSING SAID MIXTURE AND SEPARATINGA LIQUID HYDROCARBON MATERIAL FROM LIQUID HYDROFLUORIC ACID, RETURNINGAT LEAST A PORTION OF SAID LIQUID HYDROFLUORIC ACID TO SAID ZONE AS SAIDREFLUX, SEPARATELY ALKYLATING ISOBUTANE CONTAINED IN SAID LIQUIDHYDROCARBON MATERIAL TO PRODUCE NORMALLY LIQUID ISOPARAFFINS BOILING INTHE GASOLINE RANGE, PASSING A RESULTING CRUDE ALKYLATE TO A SEPARATINGMEANS, REMOVING FROM THE AFORESAID REACTION-FRACTIONAL DISTILLATION ZONEAS A HIGHBOILING PRODUCT A LIQUID HYDROCARBON MATERIAL FREE FROM HYROGENFLUORIDE AND COMPRISING C6AND-HIGHER HYDROCARBONS PRODUCED IN SAID ZONE,PASSING THE LAST SAID LIQUID HYDROCARBON MATERIAL TO THE AFORESAIDSEPARATING MEANS, AND REMOVING FROM SAID SEAPRATING MEANS AS A PRODUCTOF THE PROCESS AN ISOPARAFFINS HYDROCARBON MATERIAL COMPRISINGISOPARAFFINS BOILING IN THE GASOLINE RANGE PRODUCED FROM ISOPENTANE INSAID ZONE, AND PRODUCED FROM SAID ISOBUTANE ALKYLATION.